SimmsFishFence

1. Introduction

Simms Creek is a small, 3rd order stream that drains an area of ~1,800 ha into the Salish Sea, near Campbell River’s Willow Point neighborhood. The lower reach of Simms Creek (~3 km of channel, east of Dogwood Street), is contained within a narrow urban green way that is bordered by residential properties. From Dogwood Street Road the streams runs for ~ 2 km to the Inland Highway and is protected within Beaver Lodge Lands, upstream of the Inland Highway, >1.5 km of tributary channel is located within private forest lands in various stages of regeneration.

Chum, Chinook, Pink and Coho salmon have all been observed in Simms Creek, as well as Coastal Cutthroat Trout (CCT), Rainbow Trout and steelhead. More recent monitoring (i.e., this dataset), suggest that Coho Salmon (CO) and CCT are the primary species within Simms Creek, both of which are present within the stream year round - though a small number of juvenile Chinook Salmon were identified in 2024.

Greenways Land Trust has supported Simms Creek Stewards for +20 years, including operation of a fish fence near the mouth of the stream since 2008. Juvenile and adult fish moving past the fence are tallied each spring and fall, respectively. The objective of this project is to explore the juvenile fence dataset. All work is being done strictly for fun and out of personal curiosity. Any feedback, input, or support is welcome. Also, I have a soft spot for CCT, so be warned that effort and results will be slightly trout biased. Let’s take a look at what has been completed to date. It’s a tremendous amount of work and all volunteers and supporters should be commended!

Download Fence Data (.csv) Download Enviromental Data (.csv)

2. Fence Operation

2.1. Monitoring Effort

The Simms Creek fish fence has operated annually since 2008, with the exception of 2020 and 2021 when operations were paused due to the COVID-19 Pandemic and in the spring of 2023 when federal employees were on strike.

Spring surveys target out migrating juvenile Coho Salmon but also capture an impressive number of CCT and have even captured some Chinook Salmon. Spring fence monitoring has started as early as April 03, however, most surveys (50%) don’t start until April 18. In each monitoring year, the fence has operated continuously (e.g., sampling occurred at least daily) from April 28 to May 30. Surveys have continued as late as June 13, but most (50%) are terminated by June 06.

Fall surveys to count the number returning adult Coho, Chinook, Chum and Pink Salmon and also intercept a small number of CCT. In the fall, surveys have started as early as September 26, however, most surveys (50%) have started on October 08. In each monitoring year, surveys have occurred continuously (e.g., sampling occurred daily) from October 23 to November 16. Surveys have continued as late as December 10 and no surveys have occurred later than December 02.

Monitoring Effort Tables and Figures

Table 1. Sampling Summary

Table 2. Annual Spring and Fall Trap Operation Periods

Table 2. Annual spring and fall trap operation periods.

	Spring Sampling			Fall Sampling
Year	# Days Sampled	Start	End	# Days Sampled	Start	End
2008	41	Apr-21	May-31	40	Oct-14	Nov-22
2009	50	Apr-19	Jun-07	40	Oct-14	Nov-22
2010	42	Apr-19	May-30	35	Oct-23	Nov-26
2011	49	Apr-19	Jun-06	46	Oct-18	Dec-02
2012	50	Apr-16	Jun-04	50	Oct-14	Dec-02
2013	49	Apr-14	Jun-01	62	Sep-29	Dec-01
2014	45	Apr-24	Jun-07	58	Oct-04	Nov-30
2015	52	Apr-10	May-31	62	Oct-08	Dec-08
2016	63	Apr-03	Jun-04	60	Oct-07	Dec-05
2017	68	Apr-05	Jun-11	56	Oct-11	Dec-05
2018	52	Apr-21	Jun-11	58	Oct-08	Dec-04
2019	51	Apr-18	Jun-07	64	Oct-08	Dec-10
2020	0	COVID	-	0	-	-
2021	0	COVID	-	0	-	-
2022	47	Apr-28	Jun-13	37	Oct-11	Nov-16
2023	0	DFO Strike	-	45	Sep-26	Nov-17
2024	55	Apr-12	Jun-05	0	-	-

2.2 Stream Conditions

During each daily trap visit, volunteers record measures of water temperature, pH, Total Suspended Sediment (TSS), dissolved oxygen, and water level (stage). Mean annual measures of each parameter are presented below for the spring and fall monitoring periods (Table 3 and Table 4, Figure 2).

Stream Conditions Figures and Tables

Table 3. Spring Condition Table

Table 3. Stream conditions during spring trap operation.

Year	Spring Monitoring
	Air Temp. (°C)		Water Temp. (°C)		pH .		DO (mg/L)		TDS (ppm)		Water Level (m)
	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
2008	9.5	4.0	10.5	2.8	7.1	0.3	10.8	0.8	67.8	36.8	0.2	0.0
2009	11.8	3.0	10.3	2.4	7.1	0.2	10.3	0.8	136.4	26.2	0.3	0.0
2010	9.5	2.2	10.0	1.6	8.2	0.3	10.5	1.8	110.2	17.4	0.2	0.1
2011	9.8	2.3	9.8	2.1	6.7	0.3	9.1	1.0	95.5	11.7	0.2	0.0
2012	11.0	2.1	10.2	1.7	7.4	0.8	9.9	1.4	99.4	17.2	0.2	0.1
2013	10.3	2.9	10.1	2.0	7.9	0.3	11.5	0.9	100.6	14.9	0.2	0.1
2014	12.2	2.4	11.3	1.7	8.1	0.5	9.7	0.6	97.8	19.2	0.2	0.1
2015	10.5	3.4	11.0	2.5	8.1	0.2	9.4	0.8	106.7	22.2	0.2	0.4
2016	11.4	2.8	11.7	1.8	7.1	0.4	10.2	1.5	111.3	20.1	0.1	0.0
2017	9.6	3.0	10.2	2.3	8.2	0.4	10.9	2.2	77.8	25.6	0.3	0.1
2018	10.7	2.5	8.7	1.3	8.8	1.4	14.2	1.6	153.9	21.2	0.1	0.0
2019	11.2	2.7	11.9	2.3	8.0	0.2	8.6	0.7	129.0	25.7	0.1	0.1
2022	11.7	2.5	12.2	16.0	7.5	0.3	-	-	83.0	17.2	0.2	0.1
2023	-	-	-	-	-	-	-	-	-	-	-	-
2024	12.1	2.2	10.3	2.1	7.7	0.4	10.2	0.9	129.8	30.0	0.1	0.0

Table 4. Fall Condition Table

Table 4. Stream conditions during fall trap operation.

Year	Fall Monitoring
	Air Temp. (°C)		Water Temp. (°C)		pH .		DO (mg/L)		TDS (ppm)		Water Level (m)
	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
2008	6.3	3.0	8.8	1.3	7.3	0.4	10.5	0.4	120.2	30.9	0.4	0.1
2009	6.8	3.3	8.7	1.9	7.6	0.2	10.6	1.9	105.0	28.7	0.5	0.2
2010	4.9	4.7	7.9	2.7	7.0	0.2	9.5	0.9	110.9	31.1	0.6	0.9
2011	4.9	3.0	7.0	1.8	7.3	0.6	9.7	0.5	112.7	30.1	0.3	0.3
2012	5.9	3.2	7.8	1.7	7.5	0.2	10.8	1.6	116.1	29.6	0.4	0.2
2013	6.1	3.1	8.0	2.0	7.7	0.1	10.5	0.7	119.8	30.6	0.3	0.1
2014	7.3	5.0	9.6	3.2	7.9	0.2	10.0	1.2	85.3	29.8	0.3	0.1
2015	6.0	4.3	8.5	3.0	8.2	0.2	10.2	2.1	97.1	29.5	0.3	0.2
2016	7.8	3.1	9.3	1.8	8.1	1.3	9.3	1.3	54.0	9.2	0.5	0.2
2017	4.8	3.3	8.4	1.9	8.1	0.7	12.8	1.4	101.8	38.2	0.3	0.2
2018	6.4	3.5	9.2	1.9	7.9	0.3	10.4	0.6	88.8	29.0	0.3	0.1
2019	5.2	3.8	8.2	2.3	7.6	0.1	11.5	1.0	103.9	26.6	0.2	0.1
2022	6.9	4.9	8.4	2.5	7.8	0.2	10.1	-	126.9	83.3	0.2	0.6
2023	8.3	5.4	9.6	2.4	7.8	0.2	10.7	0.7	66.4	66.1	0.2	0.1
2024	-	-	-	-	-	-	-	-	-	-	-	-

Figure 2. Spring and Fall Condition Plot

2.3. Annual Captures

Since 2008, a total of 5,046 juvenile CCT and 8,216 juvenile Coho Salmon have been captured during spring trapping. Annual captures of CCT have ranged from 45 to 849 (mean = 360) while CO captures have varied from 335 to 913 with an overall mean of 587 fish (Figure 3 and Figure 4, Table 5 and Table 6).

As expected, most fish are captured in the Spring. Catches of CCT have ranged from 45 to 849 during spring (mean = 360 \(\pm\) 276.5) compared to only 1 to 9 fish during fall (mean = 2 \(\pm\) 2.8).

Annual Captures Figures and Tables

Figure 3. Spring - Total annual catches

Table 5. Spring - Total annual catches

**Table 5. Spring capture summary - capture timing, total captures and length of CCT and Coho Salmon.**

				CCT								Coho Salmon								Total
	Sample Period			Capture Timing			Fork Length (mm)					Capture Timing			Fork Length (mm)					(CT+CO)
Year	Start	End	# Days Sampled	Med.	Min	Max	n	Mean	SD	Min	Max	Med.	Min	Max	n	Mean	SD	Min	Max	n
2008	Apr-21	May-31	41	May-20	Apr-21	May-31	756	139.1	27.6	90	280	May-17	Apr-25	May-31	512	118.1	10.7	84.0	150	1268
2009	Apr-19	Jun-07	50	May-16	Apr-20	Jun-03	225	163.3	22.9	115	265	May-20	Apr-24	Jun-07	658	100.2	11.0	11.0	160	883
2010	Apr-19	May-30	42	May-13	Apr-19	May-29	502	149.7	26.1	110	285	May-13	Apr-20	May-30	477	118.0	15.7	80.0	183	979
2011	Apr-19	Jun-06	49	May-15	Apr-23	Jun-05	624	155.3	32.5	95	400	May-17	Apr-20	Jun-06	602	113.1	12.8	80.0	147	1226
2012	Apr-16	Jun-04	50	May-08	Apr-23	Jun-01	465	160.1	33.7	80	335	May-13	Apr-16	Jun-04	689	107.8	12.4	75.0	145	1154
2013	Apr-14	Jun-01	49	May-09	Apr-16	May-30	461	161.4	26.5	95	350	May-12	Apr-15	Jun-01	913	106.7	9.9	83.0	150	1374
2014	Apr-24	Jun-07	45	May-09	Apr-27	Jun-02	76	142.1	29.2	70	310	May-12	Apr-26	Jun-05	376	103.2	12.4	80.0	223	452
2015	Apr-10	May-31	52	May-09	Apr-15	May-28	141	158.1	37.4	85	260	May-13	Apr-11	May-31	761	109.3	11.7	78.0	152	902
2016	Apr-03	Jun-04	63	Apr-26	Apr-05	May-15	77	147.5	37.4	88	250	May-05	Apr-05	Jun-04	817	108.0	13.4	0.0	162	894
2017	Apr-05	Jun-11	68	May-24	Apr-20	Jun-09	65	185.1	64.0	120	470	May-20	Apr-05	Jun-11	335	113.4	12.8	80.0	162	400
2018	Apr-21	Jun-11	52	May-04	Apr-26	May-27	45	167.4	28.2	120	230	May-19	Apr-21	Jun-11	647	101.4	11.1	9.0	170	692
2019	Apr-18	Jun-07	51	May-06	Apr-18	May-30	571	146.1	27.6	95	260	May-13	Apr-24	Jun-05	405	115.4	12.9	10.7	152	976
2022	Apr-28	Jun-13	47	May-19	Apr-29	Jun-13	189	168.5	33.6	98	430	May-21	Apr-28	Jun-10	366	113.7	13.0	80.0	170	555
2024	Apr-12	Jun-05	55	Apr-29	Apr-17	Jun-03	849	159.8	37.1	50	360	May-10	Apr-18	Jun-04	658	97.5	17.6	48.0	174	1507

Figure 4. Fall - Total annual catches

Table 6. Fall - Total annual catches

**Table 6. Fall capture summary - capture timing, total captures and length of CCT and Coho Salmon.**

				CCT								Coho Salmon
	Sample Period			Capture Timing			Fork Length (mm)					Capture Timing			Fork Length (mm)
Year	Start	End	# Days Sampled	Med.	Min	Max	n	Mean	SD	Min	Max	Med.	Min	Max	n	Mean	SD	Min	Max
2008	Oct-14	Nov-22	40	Nov-03	Nov-03	Nov-03	1	440.0	-	440	440	Nov-02	Oct-31	Nov-03	5	638.0	78.9	540	720
2009	Oct-14	Nov-22	40	-	-	-	0	-	-	-	-	Nov-03	Oct-17	Nov-18	12	648.3	84.1	490	790
2010	Oct-23	Nov-26	35	Nov-11	Nov-11	Nov-11	1	290.0	-	290	290	Oct-25	Oct-24	Nov-22	37	640.1	91.5	405	780
2011	Oct-18	Dec-02	46	-	-	-	0	-	-	-	-	Nov-12	Oct-26	Nov-23	30	650.5	82.9	370	795
2012	Oct-14	Dec-02	50	Oct-28	Oct-28	Oct-28	1	580.0	-	580	580	Nov-01	Oct-14	Nov-20	17	583.2	107.1	300	690
2013	Sep-29	Dec-01	62	-	-	-	0	-	-	-	-	Nov-06	Nov-02	Nov-18	83	631.7	59.7	490	790
2014	Oct-04	Nov-30	58	Oct-28	Oct-28	Oct-28	1	430.0	-	430	430	Oct-28	Oct-15	Nov-27	91	627.8	87.8	330	830
2015	Oct-08	Dec-08	62	-	-	-	0	-	-	-	-	Nov-08	Oct-12	Dec-02	77	600.0	89.4	350	750
2016	Oct-07	Dec-05	60	-	-	-	0	-	-	-	-	Nov-01	Oct-24	Nov-17	9	632.8	77.9	510	750
2017	Oct-11	Dec-05	56	Nov-19	Nov-19	Nov-19	1	470.0	-	470	470	Nov-15	Oct-18	Dec-04	19	592.4	133.3	330	770
2018	Oct-08	Dec-04	58	Nov-01	Nov-01	Nov-01	1	330.0	-	330	330	Nov-14	Oct-26	Nov-28	25	605.5	91.0	380	790
2019	Oct-08	Dec-10	64	Oct-16	Oct-16	Oct-16	1	390.0	-	390	390	Oct-25	Oct-16	Nov-17	22	566.8	110.2	340	710
2022	Oct-11	Nov-16	37	-	-	-	0	-	-	-	-	Nov-03	Oct-24	Nov-06	125	612.7	97.5	220	750
2023	Sep-26	Nov-17	45	Nov-02	Nov-02	Nov-16	9	239.1	108.9	152	430	Oct-18	Oct-11	Nov-16	272	571.3	96.5	220	740

2.4 Length Frequency

The length frequency figures shown below shed light on the population structure and behaviours of Coho Salmon and CCT in Simms Creek. The lengths of CCT (50 mm to 223 mm) and Coho Salmon (48 mm to 223 mm) measured at the fence suggest multiple age classes of juveniles are moving out of the system each spring. Assuming that CO <100 mm are Age 0 and CO >100 mm are Age 1 would suggest that 55.20% of all overall migrants are Age 0 and the remainder are Age 1. A wider range of age classes is likely present among CCT, including Age 0 fish (~<80 mm) up to mature fish > 230 mm and upwards of 3+ years.

Mature CCT >230 mm represent <1.90% of the total catch of CCT. However, all mature CCT >230 mm were moving downstream, suggesting that they either 1) moved upstream and spawned prior to the start of fence operation or 2) had overwintered in Simms Creek and were follow fry out in the spring - whether this was their first movement to the ocean is unknown.

Length Frequency Table and Figures

Figure 5. Length Frequency of all CCT

Figure 6. Length frequency of Coastal CCT across years.

Figure 7. Length frequency of all Coho Salmon.

Figure 8. Length frequency of Coho Salmon across years.

2.5 Age Composition

No scale data has been collected during juvenile enumeration work on Simms Creek. However, information collected on systems within the region suggests we can loosely apply the following age classes to juvenile CT and CO:

• CT < 80 ~ Age-0
• CT < 120 ~ Age-1
• CT < 200 ~ Age-2
• CT > 200 ~ Age-2+
• CO < 80 ~ Age-0
• CO < 120 ~ Age-1
• CO > 120 ~ Age-1+

Applying these age bins to the length frequency data suggests that CCT are range in age from Age-1 to Age 3+, but are primarily Age-2 (Figure 9), while CO are almost exclusively Age-1 (Figure 10). Interestingly, Age-0 CO were present in 2009 and 2024, but not other years. While this may be coincidental, it’s worth noting that the peak juvenile CCT counts were recorded in 2008 and 2024. There are a number of mechanisms that may explain why Age-0 CO were first observed in 2024: 1) they weren’t recorded in past years, CO emigrated out of Simms Creek earlier than normal due to high CT abundance.

Figure 9. Age composition across years.

Figure 10. Size by age class across years.

2.6. Migration Timing

2.4.1 Spring Outmigration

Outmigrating juvenile CCT and Coho Salmon were first encountered at the trap over a similar period, from October 16 to November 19 (mean \(\pm\) SD = November 01 \(\pm\) 10.1 days) for CCT and October 11 to November 02 for Coho (mean \(\pm\) SD = October 20 \(\pm\) 7 days). On average 50% of all CCT had passed the fence by November 02\(\pm\) 10.1 days while half of Coho Salmon migrants had passed the fence by November 05\(\pm\) 8 days. Despite similarities in when migrations started and the timing that most migrants had past the fence, there was a noticeable difference in the timing of peak migrations (the date when the greatest number of fish passed the fence). For Coastal CCT, the overall mean \(\pm\) SD peak migration occurred on November 01(\(\pm\) 10.1 days) (Figure 5) whereas overall mean peak Coho Salmon migration occurred more than a week later on October 30 (\(\pm\) 11.4 days) (Figure 6). Total number of daily captures of CCT and Coho Salmon per year are presented in Figure 6 and Figure 7, respectively.

2.4.2 Fall Return Timing

Adult Coho Salmon have been detected at the fence as early as October 11 and as late as November 02, though most of the run (50%) arrive within a week of November 05 (Figure 14 to 19). Relative to spring sampling, CCT are encountered less frequently in the fall and arrival timing appears to be considerably more variable (Figure 20 to 22).

Spring and Fall Migration Timing Tables and Figures

Figure 11. Spring - Overall Capture Timing

Figure 12. Spring - Daily captures of CCT per year

Figure 13. Spring - Total daily captures of Coho Salmon per year

Figure 14. Fall - Total daily captures of Coho Salmon per year

Figure 15. Fall - Daily captures of CCT per year

2.6 What are these fish doing???

CCT show incredible diversity in the timing of their life history behaviours. Throughout their range, spawning has been documented in nearly every month of the year. In Puget Sound for instance, spawning has been reported from November through March and timing is highly variable between years (Losee et al. 2016). The spawn timing of CCT in Simms Creek is unknown, or at least undocumented, however, I would assume it occurs during a similar period to Puget Sound and is equally variable.

The current dataset does provide some insight on spawn timing. Presumably, spawners will be >150 mm in length.

FINISH WRITING THIS SECTION

3. Survival

3.1 What may be driving juvenile abundance

{ 9. Survival, echo = FALSE, warning = FALSE, message = FALSE, include = FALSE} source("SourceFiles/9. Survival.R")

To estimate the number of Coho Salmon that survive from egg to fry, we need to make a number of assumptions:

- All adult Coho Salmon that enter Simms Creek and all juvenile Coho Salmon that outmigrate from Simms Creek are enumerated.  
- All adult Coho Salmon that pass the fence will successfully spawn.
- The sex ratio of adults is equal (50% are female, excluding jacks which are assumed male).
- Each female will deposit ~2,600 eggs.

Importantly, we also need to consider the proportion of juveniles from each age-class the emigrate each year (and assume juvenile age assignments are accurate). Fish that outmigrate as Age-0 fry will be progeny of fish that spawned the previous fall, while fish that emigrate at Age-1 would have spent a full year in the stream (i.e., spawned 2 falls previous) and Age-1+ fish would have spawned 3 years previous. Using this information, we can then calculate the total number of juveniles produced by each spawning event to calculate egg-to-fry survival.

3.2 What about marine survival (from smolt to spawn)

Additional assumptions are required to estimate the number of juveniles that survive to return as adults:

- Adults spend ~18-20 months at sea (1 winter), regardless of whether they leave Simms Creek as Age-0 or Age-1.
- Jacks return to Simms Creek after ~6-8 months at sea (0 winters). 
- All Coho Salmon that are enumerate at the fence originated from Simms Creek (i.e., there are no hatchery fish or strays from neighbouring streams).

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3. Fall Fence Operation

3.1. Monitoring Effort